From 212787e9f137b4a89cdb4362f8b8de873c67a96f Mon Sep 17 00:00:00 2001
From: Daniel Dietrich <cafebab3@gmail.com>
Date: Sun, 31 Mar 2019 23:06:54 +0200
Subject: [PATCH] Fixes issue #2401 (#2403)

---
 vavr/generator/Generator.scala              | 31 +++++++++--
 vavr/src-gen/main/java/io/vavr/API.java     | 58 ++++++++++++---------
 vavr/src-gen/test/java/io/vavr/APITest.java | 15 ++++++
 3 files changed, 73 insertions(+), 31 deletions(-)

diff --git a/vavr/generator/Generator.scala b/vavr/generator/Generator.scala
index 05e37a2bd7..c92a1461da 100644
--- a/vavr/generator/Generator.scala
+++ b/vavr/generator/Generator.scala
@@ -960,7 +960,13 @@ def generateMainClasses(): Unit = {
 
                   @Override
                   public boolean isDefinedAt(T obj) {
-                      return $Objects.equals(obj, prototype);
+                      if (obj == prototype) {
+                          return true;
+                      } else if (prototype != null && prototype.getClass().isInstance(obj)) {
+                          return $Objects.equals(obj, prototype);
+                      } else {
+                          return false;
+                      }
                   }
               };
           }
@@ -1205,7 +1211,7 @@ def generateMainClasses(): Unit = {
 
                           @Override
                           public boolean isDefinedAt(T obj) {
-                              return obj != null && type.isAssignableFrom(obj.getClass());
+                              return type.isInstance(obj);
                           }
                       };
                   }
@@ -1241,12 +1247,12 @@ def generateMainClasses(): Unit = {
                               @SuppressWarnings("unchecked")
                               @Override
                               public boolean isDefinedAt(T obj) {
-                                  if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                                      return false;
-                                  } else {
+                                  if (type.isInstance(obj)) {
                                       final $unapplyTupleType u = unapply.apply(obj);
                                       return
                                               ${(1 to i).gen(j => s"((Pattern<U$j, ?>) p$j).isDefinedAt(u._$j)")(" &&\n")};
+                                  } else {
+                                      return false;
                                   }
                               }
                           };
@@ -2606,6 +2612,8 @@ def generateTestClasses(): Unit = {
       val API = im.getType("io.vavr.API")
       val AssertionsExtensions = im.getType("io.vavr.AssertionsExtensions")
       val ListType = im.getType("io.vavr.collection.List")
+      val StreamType = im.getType("io.vavr.collection.Stream")
+      val SeqType = im.getType("io.vavr.collection.Seq")
       val MapType = im.getType("io.vavr.collection.Map")
       val OptionType = im.getType("io.vavr.control.Option")
       val FutureType = im.getType("io.vavr.concurrent.Future")
@@ -2971,6 +2979,19 @@ def generateTestClasses(): Unit = {
                 assertThat(Case($$(ignored -> false), 1).isDefinedAt(null)).isFalse();
             }
 
+            @$test
+            public void shouldPassIssue2401() {
+                final $SeqType<String> empty = $StreamType.empty();
+                try {
+                    final String matched = Match(empty).of(
+                            Case($$($ListType.empty()), ignored -> "list")
+                    );
+                    fail("expected MatchError");
+                } catch (MatchError err) {
+                    // ok!
+                }
+            }
+
             // -- Match patterns
 
             static class ClzMatch {}
diff --git a/vavr/src-gen/main/java/io/vavr/API.java b/vavr/src-gen/main/java/io/vavr/API.java
index 9d2b7ed811..28dbae6338 100644
--- a/vavr/src-gen/main/java/io/vavr/API.java
+++ b/vavr/src-gen/main/java/io/vavr/API.java
@@ -4988,7 +4988,13 @@ public T apply(T obj) {
 
             @Override
             public boolean isDefinedAt(T obj) {
-                return Objects.equals(obj, prototype);
+                if (obj == prototype) {
+                    return true;
+                } else if (prototype != null && prototype.getClass().isInstance(obj)) {
+                    return Objects.equals(obj, prototype);
+                } else {
+                    return false;
+                }
             }
         };
     }
@@ -5379,7 +5385,7 @@ public T apply(T obj) {
 
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        return obj != null && type.isAssignableFrom(obj.getClass());
+                        return type.isInstance(obj);
                     }
                 };
             }
@@ -5403,12 +5409,12 @@ public T1 apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple1<U1> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1);
+                        } else {
+                            return false;
                         }
                     }
                 };
@@ -5433,13 +5439,13 @@ public Tuple2<T1, T2> apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple2<U1, U2> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1) &&
                                     ((Pattern<U2, ?>) p2).isDefinedAt(u._2);
+                        } else {
+                            return false;
                         }
                     }
                 };
@@ -5464,14 +5470,14 @@ public Tuple3<T1, T2, T3> apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple3<U1, U2, U3> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1) &&
                                     ((Pattern<U2, ?>) p2).isDefinedAt(u._2) &&
                                     ((Pattern<U3, ?>) p3).isDefinedAt(u._3);
+                        } else {
+                            return false;
                         }
                     }
                 };
@@ -5496,15 +5502,15 @@ public Tuple4<T1, T2, T3, T4> apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple4<U1, U2, U3, U4> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1) &&
                                     ((Pattern<U2, ?>) p2).isDefinedAt(u._2) &&
                                     ((Pattern<U3, ?>) p3).isDefinedAt(u._3) &&
                                     ((Pattern<U4, ?>) p4).isDefinedAt(u._4);
+                        } else {
+                            return false;
                         }
                     }
                 };
@@ -5529,9 +5535,7 @@ public Tuple5<T1, T2, T3, T4, T5> apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple5<U1, U2, U3, U4, U5> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1) &&
@@ -5539,6 +5543,8 @@ public boolean isDefinedAt(T obj) {
                                     ((Pattern<U3, ?>) p3).isDefinedAt(u._3) &&
                                     ((Pattern<U4, ?>) p4).isDefinedAt(u._4) &&
                                     ((Pattern<U5, ?>) p5).isDefinedAt(u._5);
+                        } else {
+                            return false;
                         }
                     }
                 };
@@ -5563,9 +5569,7 @@ public Tuple6<T1, T2, T3, T4, T5, T6> apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple6<U1, U2, U3, U4, U5, U6> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1) &&
@@ -5574,6 +5578,8 @@ public boolean isDefinedAt(T obj) {
                                     ((Pattern<U4, ?>) p4).isDefinedAt(u._4) &&
                                     ((Pattern<U5, ?>) p5).isDefinedAt(u._5) &&
                                     ((Pattern<U6, ?>) p6).isDefinedAt(u._6);
+                        } else {
+                            return false;
                         }
                     }
                 };
@@ -5598,9 +5604,7 @@ public Tuple7<T1, T2, T3, T4, T5, T6, T7> apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple7<U1, U2, U3, U4, U5, U6, U7> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1) &&
@@ -5610,6 +5614,8 @@ public boolean isDefinedAt(T obj) {
                                     ((Pattern<U5, ?>) p5).isDefinedAt(u._5) &&
                                     ((Pattern<U6, ?>) p6).isDefinedAt(u._6) &&
                                     ((Pattern<U7, ?>) p7).isDefinedAt(u._7);
+                        } else {
+                            return false;
                         }
                     }
                 };
@@ -5634,9 +5640,7 @@ public Tuple8<T1, T2, T3, T4, T5, T6, T7, T8> apply(T obj) {
                     @SuppressWarnings("unchecked")
                     @Override
                     public boolean isDefinedAt(T obj) {
-                        if (obj == null || !type.isAssignableFrom(obj.getClass())) {
-                            return false;
-                        } else {
+                        if (type.isInstance(obj)) {
                             final Tuple8<U1, U2, U3, U4, U5, U6, U7, U8> u = unapply.apply(obj);
                             return
                                     ((Pattern<U1, ?>) p1).isDefinedAt(u._1) &&
@@ -5647,6 +5651,8 @@ public boolean isDefinedAt(T obj) {
                                     ((Pattern<U6, ?>) p6).isDefinedAt(u._6) &&
                                     ((Pattern<U7, ?>) p7).isDefinedAt(u._7) &&
                                     ((Pattern<U8, ?>) p8).isDefinedAt(u._8);
+                        } else {
+                            return false;
                         }
                     }
                 };
diff --git a/vavr/src-gen/test/java/io/vavr/APITest.java b/vavr/src-gen/test/java/io/vavr/APITest.java
index d786a1a333..9e1c51c8ff 100644
--- a/vavr/src-gen/test/java/io/vavr/APITest.java
+++ b/vavr/src-gen/test/java/io/vavr/APITest.java
@@ -31,6 +31,8 @@
 
 import io.vavr.collection.List;
 import io.vavr.collection.Map;
+import io.vavr.collection.Seq;
+import io.vavr.collection.Stream;
 import io.vavr.concurrent.Future;
 import io.vavr.control.Option;
 import io.vavr.control.Try;
@@ -1406,6 +1408,19 @@ public void shouldReturnNoneWhenApplyingCaseGivenPredicateAndValue() {
         assertThat(Case($(ignored -> false), 1).isDefinedAt(null)).isFalse();
     }
 
+    @Test
+    public void shouldPassIssue2401() {
+        final Seq<String> empty = Stream.empty();
+        try {
+            final String matched = Match(empty).of(
+                    Case($(List.empty()), ignored -> "list")
+            );
+            fail("expected MatchError");
+        } catch (MatchError err) {
+            // ok!
+        }
+    }
+
     // -- Match patterns
 
     static class ClzMatch {}